How to refresh list item values before report is run?

Question

We have two SELECT LIST items (drop boxes) on our report. One SELECT LIST has values of "World Region" (e.g. NORTH AMERICA, SOUTH AMERICA, EUROPE, ASIA)
the other SELECT LIST has values of "Subregion" (e.g. NORTHERN EUROPE, SOUTHERN EUROPE, SOUTHEAST ASIA etc...)
The values in the Subregion list are dependent on the value that is chosen from the "World Region" List. Can someone tell up how to update the values in the Subregion list BEFORE we submit the page? We can get these values to update (via sql query) when the page is submitted but that is only happening after the report gets run- which is not what we want. We want the user to select a Region from one SELECT LIST and then see all the qualifying Subregions for that Region in the Subregion SELECT LIST. Only after both Region and Subregion have been selected do we want to run the report. Thank for any help on this.

Answer 1

hey john--
john) things like Scott's reference to "The name of the LOV Item". What does this really mean?
raj) in htmldb there's a concept of items at the page and at the app level. page level items have ui component associated with them. in scott's explanation above, he's talking about using a page-level item with a "Display as" type of "select list w/submit" for your first select list. in that case, he's suggesting you have one select list item drive the values of another. when the self-submitting select list submits the page, it sets an htmldb built-in variable called :REQUEST to the name of the self-submitting select list item. in your follow-up post's example, that'd be "REGION_LIST". scott was explaining how you could control the functionality on your page by adding conditions to things like...
:REQUEST = 'REGION_LIST'
...or using declarative Condition options like "Request = Expression 1" and then putting the string "REGION_LIST" in that Expression1 field. so in your case, you have a report region that you don't want displayed until the user's done selecting from your Subregion list. an easy way to handle that would be to add a hidden item (where "Display as" is set to "Hidden") to your page, for example :P1_LAST_REQUEST, to store the last value of :REQUEST. put a Computation on your page that populates :P1_LAST_REQUEST with :REQUEST each time the page is submitted. then put a Condition on your report region that makes it only render when :P1_LAST_REQUEST != 'REGION_LIST'. so this way your users can select a Region and have the page submit itself. the page will then redraw with the values of subregion list correctly populated (you'd presumably use :REGION_LIST in your subregion LOV query to achieve the filtered values) w/o your report region displayed. the user would then select a correct subregion and click some sort of "run my report" button. this time when the page redraws, :P1_LAST_REQUEST would be set so something other than "REGION_LIST" (it'd be set to whatever you named your "run my report button") and so your report region would display as desired.
hope this helps,
raj